1. Technical Field
The inventive arrangements relate generally to methods and apparatus for providing advanced operating features for recording data to recordable DVD media, and more particularly to a method and apparatus for tracking defective sectors in recordable DVD media.
2. Description of the Related Art
Various devices have been developed to enable consumers to record video and/or audio programs for later presentation. Such devices include tape recorders, video cassette recorders, recordable compact disks, and most recently, recordable digital versatile disks (DVD). Hard drives and magneto optical disks have also been used. A DVD in which data can be recorded once only, and thereafter is essentially a DVD read only memory, is referred to by the acronym DVD-R. The acronym DVD-R also has been used generally to refer to write-once, or record-once, technology.
In contrast to DVD-R, several formats exist in which data can be recorded to a DVD, erased and re-recorded. In sum, such a DVD can be overwritten or rewritten. These DVDs typically are referred to by the acronyms DVD-RAM, DVD-RW and DVD+RW. Although, as of this time no uniform industry standard has been adopted, the acronyms DVD-RAM, DVD-RW and DVD+RW have been used generally to refer to the respective re-writable DVD technologies. Still, reference herein to re-writable DVD technology, devices and methods and recordable DVD media is generally intended to encompass all of the standards which are now being used, as well as those which may be developed in the future.
Present DVDs can have a logical file structure in which audio-video content can be stored. Specifically, as shown in FIG. 7, at the top of the file structure hierarchy of a DVD 700, one or more titles 701 can exist which can loosely correlate to program episode titles. Titles 701 can consist of control data 702 in addition to one or more Video Object Sets 703 (VOBS). The control data 702 can contain information for managing the title 701. Each VOBS 703 can include a plurality of Video Objects (VOB) 704. Each VOB 704 preferably includes a plurality of Cells 705. Each Cell 705 preferably includes a plurality of Video Object Units (VOBU) 706. Each VOBU 706 roughly correlates to a group of pictures which is the smallest addressable chunk in the DVD 700.
Notably, each VOBU 706 can contain an integer number of video frames. As such, each VOBU 706 can contain 0.4 to 1.0 seconds of presentation material. A typical VOBU 706 in a commercial motion picture can contain 0.5 second of presentation material. Notably, each VOBU 706 can include a sequence of packs 707 positioned in recording order. Preferably, each VOBU can begin with a navigation pack 708 (NV_PCK or NAV_PACK) which can be followed by audio-visual data packs 709, for example video packs (V_PCK), audio packs (A_PCK) and sub-picture packs (SP_PCK). The NV-PCK 708 can contain navigation information, which can be useful in implementing trick modes of operation. The NV_PCK 708 also can include presentation control information (PCI) and data search information (DSI).
Present DVDs can store data using the Universal Disc Format (UDF) specification. As such, present DVDs can include a directory and set of files within the UDF file format. FIG. 8 illustrates the directory structure of a typical DVD. According to the DVD-ROM specification, all files in a DVD are stored in directories 801, 810, 815 and 820 below the root directory 800. In particular, DVD-Video data can be stored a single directory referred to as the VIDEO_TS directory 801. The VIDEO_TS directory 801 can contain a Video Manager and one or more Titles. As illustrated in FIG. 8, the Video Manager can include a Video Manager information file 802, a Video Manager menu file 803, and a Video Manager backup file 804. Additionally, each Title can include a Video Title information file 805A, 805B, a Video Title menu 806A, 806B, one or more video object set files 807A, 807B, 808A, 808B and a Video Title Backup file 809A, 809B.
Aside from DVD-Video, DVD-Audio information can be stored in an analogous directory, AUDIO_TS 810. Furthermore, an optional, root-level directory JACKET_P 815 can contain identifying images for the DVD in three sizes including thumbnails for graphical directories of DVD collections. Notably, a DVD can include other files stored in one or more user-defined directories 820. Such directories and files typically are placed on the DVD following the DVD-Video data and are ignored by conventional DVD players.
Recordable DVD media can be used for thousands or even tens of thousands of times for recordings. For each recording, defective sectors in the recordable DVD media potentially can arise. As a result, recordable DVD media can accumulate a substantial number of defective sectors during the operational lifetime of the recordable DVD media. Yet, defective sectors in recordable DVD media can inhibit proper playback of data stored in the recordable DVD media. Specifically, defective sectors in the control data area, such as a control data VOB for a title set, can invalidate the control data. Moreover, defective sectors in video data in a VOBU can cause video freeze or blockiness. Additionally, defective sectors in audio data in a VOBU can cause audio distortion or noise. Finally, defective sectors in a menu area can damage a menu.
For analog tape recording technology, such as VCR technology, a defective portion of the video tape may not affect the quality of the signal substantially during playback. In contrast, for digital disc recording technology, a defective sector can significantly affect playback quality causing a loss of navigation information and control data, video freeze, blockiness, loss of audio information and menu corruption. As a result, if defective sectors cannot be identified prior to recording to a re-writable disc, an entire recording can be ruined. Accordingly, defective sector checking can be critical to a successful digital disc recording.
Notably, re-writable DVDs each have a defect list that is generated by the manufacturer. Those sectors which are determined to be defective are added to the defect list so that the defective sectors will be skipped during a recording session.
Notwithstanding, in most cases, defect checking cannot be performed in real-time during a recording session. Moreover, to inspect a re-writable DVD for defective sectors by scanning the entire re-writable DVD can consume several hours depending upon the capacity of the re-writable DVD and the front-end speed of the re-writable DVD recorder. Accordingly, it can be impractical to delay the user for the time required to perform the inspection prior to permitting the user to begin recording.